1. Field of the Invention
The present invention relates to a transmission unit for a hybrid vehicle. The hybrid vehicle is provided with an internal combustion engine and a motor/generator (an electric motor that functions as a generator), each output torque of these drive sources being transmitted to a variable gear unit (transmission mechanism) to achieve a vehicular run driving force by either or both of the engine and the motor.
2. Description of the Related Art
A Japanese Patent Application First Publication No. Heisei 2000-9213 (P2000-9213A) published on Jan. 11, 2000 exemplifies a previously proposed transmission unit for a hybrid vehicle.
The previously proposed transmission unit for the hybrid vehicle disclosed in the above-identified Japanese Patent Application First Publication includes: a clutch chamber formed with a first housing and a first partitioning wall; a motor chamber formed with a second housing, the first partitioning wall, and a second partitioning wall; and a transmission chamber formed with a third housing and the second partitioning wall.
A revolution of an engine is inputted to an electromagnetic clutch in the clutch chamber. An output revolution via the electromagnetic clutch is transmitted to an electric motor installed within the motor chamber and to a transmission installed within the transmission chamber through an input axle of the transmission unit.
A resolver is installed on a support of the input axle within the third housing. This resolver functions to detect a revolution position of a rotor of the motor. Then, a motor driving force control for the motor can be carried out on the basis of a detection signal of the resolver.
The electric motor in the transmission unit includes a rotor on which a North (N) pole and a South (S) pole of a permanent magnet are alternatingly aligned and a stator which is an electromagnet. The motor controller supplies a control current of the stator, detecting on which position of the rotor the N pole and S pole are placed. If, due to a tolerance accumulated during the assembly, the resolver is out of a standard position, the motor driving force cannot optimally be controlled. Hence, it is necessary to manually adjust the position of the resolver after the assembly operation of the whole transmission unit.
However, in the previously proposed transmission unit disclosed in the above-identified Japanese Patent Application, the supply of a hydraulic to an axial center oil passage disposed within the input axle is carried out from a hydraulic circuit installed within the third housing and the resolver is disposed within the third housing including the hydraulic circuit. Therefore, it becomes impossible to manually adjust the resolver itself or its position with respect to the rotor.
In addition, in order to avoid such a problem as described above, it may be considered that the hydraulic circuit is interposed between the resolver and the CVT and the resolver itself is disposed within a dry chamber.
However, in order to provide a space for the resolver, the transmission unit itself needs to be elongated in the axial direction thereof.
It is therefore an object of the present invention to provide an improved transmission unit for a hybrid vehicle in which a rotor position detector, viz., a resolver can be disposed therein without an increase in a dimension in an axial direction of the transmission unit and the assembled position of the rotor position detector can be adjusted even after the assembly of the rotor position detector into the transmission unit.
The above-described object can be achieved by providing a transmission unit for a hybrid vehicle, comprising: an electromagnetic clutch; an electric motor; a transmission comprising an input axle to input revolution from the electromagnetic clutch to the electric motor and to a transmission mechanism section thereof; and a rotor position detector to detect a revolution position of a rotor of the electric motor, the rotor position detector being disposed on the input axle of the transmission at an inner side with respect to a stator coil of the electric motor.